Klier is a surname. Notable people with the surname include:
Andreas Klier (born 1976), German road racing cyclist Cornelia Klier (born 1957), German rower Freya Klier (born 1950), German author and film director Gerd Klier (1944–2011) German footballer John Klier (1944–2007), American historian Leo Klier (1923–2005), American basketball player Philip Adolphe Klier (1845–1911) German photographer in colonial British-Burma Richard Klier (1891–?), Czech Olympic sports shooter